Optics: Applications of Reflected and Refracted LightSections: 23-6, 24-4

Total Internal Reflection n2 < n1 Light does not emerge

For Ray J, θ < θc For Ray K, θ = θc

For Ray L, θ > θc

Total Internal Reflection Used for Fiber Optics

Transmit information with light instead of electricity

Analog Signals vary the amplitude of the signalRadio, analog television

Digital SignalsLight On = 1Light Off = 0

Effects of Refraction Mirage – change in nair due to change

in tempLight ray aimed at road encounters

smaller nLight bent away from normalYou see light from sky, looks like a

puddle Sunrise, Sunset – sun’s image

refracted by earth’s atmosphere Object in liquid – appears closer to

surface than it is

Dispersion of Light ns depends on λ of light ns is greater for shorter λ

Violet light is bent more ns is smaller for longer λ

Red light is bent less

Dispersion – separation into spectrum by refraction

Dispersion of Light

Rainbows – dispersion in water droplets

Different light sources have different spectra